Dataset Information

Transcriptomics and mutagenesis analysis uncover key mechanisms involved in polymyxin B resistance and heteroresistance of the neonatal sepsis pathogen Enterobacter bugandensis

ABSTRACT: Enterobacter bugandensis is one of species from the E. cloacae complex (ECC) that has been predominantly associated to neonatal sepsis. A major concern with E. bugandensis and ECC bacteria in general is the frequent appearance of multidrug resistant isolates including those resistant to last-resort antibiotics, such as polymyxins, for which these microbes are in the ESKAPE list of global threat pathogens. Here, we investigated polymyxin B (PmB) resistance and heteroresistance in E. bugandensis by transcriptomics and a gene deletion approach using two clinical isolates. Genes encoded in the CrrAB-regulated operon including crrC and kexD were highly upregulated in both strains in the presence of PmB. We show in one of these isolates that ∆crrC and ∆kexD mutants exhibited lower levels of PmB resistance and heteroresistance than the parental strain. Moreover, the heterologous expression of CrrC and KexD proteins increased PmB resistance in a sensitive E. ludwigii clinical isolate and in the Escherichia coli K12 strain W3110. We also showed that the efflux pump AcrAB and TolC contribute to PmB resistance and heteroresistance. Deletion of the regulatory genes phoPQ and crrAB cause reduced PmB resistance and heteroresistance, while deletion of pmrAB did not have any effect. Our results also reveal that the addition of L-Ara4N into the lipid A, mediated by the arnBCADTEF operon, is critical to determine PmB resistance, while the deletion of eptA, encoding a PEtN transferase had no effect. Finally, PmB resistance did not correlate with pathogenicity in the Galleria mellonella infection model.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Enterobacter Bugandensis

SUBMITTER: Nichollas Scott

LAB HEAD: Miguel A. Valvano

PROVIDER: PXD042287 | Pride | 2024-04-05

REPOSITORIES: Pride

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Publications

Drug efflux and lipid A modification by 4-L-aminoarabinose are key mechanisms of polymyxin B resistance in the sepsis pathogen Enterobacter bugandensis.

García-Romero Inmaculada I Srivastava Mugdha M Monjarás-Feria Julia J Korankye Samuel O SO MacDonald Lewis L Scott Nichollas E NE Valvano Miguel A MA

Journal of global antimicrobial resistance 20240327

<h4>Objectives</h4>A concern with the ESKAPE pathogen, Enterobacter bugandensis, and other species of the Enterobacter cloacae complex, is the frequent appearance of multidrug resistance against last-resort antibiotics, such as polymyxins.<h4>Methods</h4>Here, we investigated the responses to polymyxin B (PMB) in two PMB-resistant E. bugandensis clinical isolates by global transcriptomics and deletion mutagenesis.<h4>Results</h4>In both isolates, the genes of the CrrAB-regulated operon, includin ...[more]

PMID: 38552872

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Project description:Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a destructive disease of wheat worldwide. Genetic resistance is the preferred method for controlling stripe rust, of which two major types are race-specific and race non-specific resistance. Race-specific resistance includes the qualitatively inherited all-stage resistance, controlled by single major resistance (R) genes. Conversely, adult-plant resistance is race non-specific, inherited quantitatively, and is durable. Previously, we characterized the gene expression signatures involved in Yr5-controlled all-stage resistance and Yr39-controlled adult-plant resistance using the Affymetrix Wheat GeneChip. For this study, we designed and constructed custom oligonucleotide microarrays containing probes for the 116 and 207 transcripts that we had found important for the Yr5 and Yr39 resistance responses, respectively. We used this custom microarray to profile the resistance responses of eight wheat genotypes with all-stage resistance (Yr1, Yr5, Yr7, Yr8, Yr9, Yr10, Yr15, and Yr17). The aim of this analysis was to identify common and unique gene expression signatures involved in race-specific resistance accross genotypes, which were used to infer information regarding the general pathways involved in all-stage resistance. Keywords: Stress response Eight wheat genotypes with defined single gene all-stage resistance to particular stripe rust (Pst) isolates were selected for this study, as well as the Pst susceptible genotype âAvocet Susceptibleâ (AVS). Near Isogenic Lines (NILs) for each of eight Yr resistance genes (Yr1, Yr5, Yr7, Yr8, Yr9, Yr10, Yr15 and Yr17) were developed at the Plant Breeding Institute, Sydney, Australia, by backcrossing the Yr gene donors with the recurrent susceptible spring wheat genotype (Triticum aestivum L.) AVS six times (AVS*6/Yr*) and selecting for the appropriate resistance at each generation. Both virulent and avirulent isolates of Pst were selected for each NIL, except for Yr15, for which no virulent isolate is currently known. Care was taken to select the fewest isolates needed to satisfy the spectrum of virulence/avirulence required, resulting in the use of six isolates identified as PST-17, PST-21, PST-43, PST-45, PST-78 and PST-AUS. Each isolate was selected and maintained on susceptible genotypes. For each of three biological replications, individual genotypes were planted in separate 25 X 42.5-cm flats using a potting mix (6 peat moss: 4 vermiculite with lime: 3 sand: 3 commercial potting mix: 2 perlite: 1.7 g/L lime: 3.3 g/L Osmocote: 2.2 g/L ammonium nitrate). Each flat consisted of three rows of six seedlings, with rows randomly assigned one of two harvest times (24 and 48 h post-inoculation). Seedlings from the 3rd row were used to monitor the expected disease responses to inoculation. Seedlings were grown to the second leaf stage (Feekes 1.2, emergence with second leaf unfolded, ~10 days after planting) in a greenhouse with a diurnal temperature cycle of 10ÂºC (2:00 am) to 25ÂºC (2:00 pm) and a 16 h light/8 h dark cycle. Inoculation was performed by misting the plants with sterile water and applying a 1:20 urediniospore:talc mixture to leaves with a sterile brush. Talc was used to aid in the spread and adhesion of spores over leaf surfaces. Control flats were treated the same way except for the absence of spores in the talc. All treatments for each biological replication were performed at 9 am Pacific Standard Time. To promote spore germination, all flats were transferred to a dew chamber (100% RH) operating at 10ÂºC in the dark for 24 h, before being placed in a growth chamber with a diurnal temperature cycle of 4ÂºC (2:00 am) to 20ÂºC (2:00 pm) and a 16 h light/8 h dark cycle. Rows of plants were harvested from all flats at the assigned times for RNA extraction.

Dataset Information

Transcriptomics and mutagenesis analysis uncover key mechanisms involved in polymyxin B resistance and heteroresistance of the neonatal sepsis pathogen Enterobacter bugandensis

Publications

Drug efflux and lipid A modification by 4-L-aminoarabinose are key mechanisms of polymyxin B resistance in the sepsis pathogen Enterobacter bugandensis.

Similar Datasets

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